Various devices have been conceived and tested for keeping bowling balls out of the gutter. Early attempts included long racks (approximately 12 ft.) which were placed in the gutters and were equipped with resilient rails for deflecting the ball. Another attempt involved rigid, half-round troughs in 12-foot sections which were inverted to cover the gutter like a dome. Even though some of these products have been field tested and offered for sale by large commercial corporations selling bowling lanes and other bowling equipment, these products for the most part have not been commercially successful. This is because these devices are either too expensive, impractical to install and maintain, or difficult to store when not in use. The length of a bowling alley is approximately 60 feet, so it can readily be appreciated that with two devices or systems required for each bowling alley, the cost per alley could be significant or the time, difficulty and expense of installation or set-up may be prohibitive, or the devices may be difficult to store, maintain or repair.
U.S. Pat. No. 4,330,122, in which I am a co-inventor with Sheinberg, represents the first practical, commercially successful solution to the problems encountered in other prior art devices. The device disclosed in our patent is an inflatable cushion or "bolster" which is filled with air only and may be pressurized slightly above atmospheric pressure to provide some rebound energy to a ball striking it. Our device has been widely accepted by the bowling industry to the extent that more than half of the bowling centers in the United States are now equipped with such inflatable cushions. These inflatable deflecting cushions solved the problems of prior attempts with a low-cost device which is easy to ship, install, set-up and store.
Very simply, the cushions are elongated cylindrical plastic tubes which are filled with air under pressure and then sealed. Each of the cushions has an air-fill aperture at one end so that inflation may be effected quickly by a motorized pump. These tubes may be filled in as little as three minutes with the proper equipment. A second aperture at the end of the deflection cushions described in the above-identified patent, is a one-way valve which is useful in "topping off" the tube after it was filled through the first aperture. That is, after the tube is inflated and the first aperture closed or sealed, the pump is then inserted in the second aperture which is provided with a simple flap-type air valve and a closure, permitting air to be forced into the tube to a pressure slightly higher than atmospheric, but permitting the pump to be removed from the aperture without losing this slight excess pressure. This results in a deflecting bumper having the desired characteristic of a slight resiliency to deflect the ball and keep it in play while not substantially reducing its speed. If an inflatable bumper is "flat" (that is, it does not have a slight pressure above atmospheric), it has a tendency to absorb the momentum of the ball and reduce the speed of a moving ball; and it also does not act properly in deflecting the ball.
The deflecting cushions described in our patent, however, suffer from one defect arising from the fact that they are used in a fairly demanding environment. For example, the cushions are typically installed by dragging or rolling them into position along the gutters, inflating the cushions, followed by sliding the cushions into proper position within the gutter. Many gutters have small edges of wood or nails projecting slightly outward, and these obstructions frequently snag the bumpers, causing slight pin holes. Over time, the bumper loses its slight excess pressure and its ability to rebound the ball diminishes. Of particular inconvenience is the fact that commercial inflatable bumpers are 56 feet long and it is difficult to locate a small leak, particularly since they are not designed to withstand a high internal pressure (like an automobile inner tube, for example). In addition, if such a small leak or pin point hole occurs during a game, the two bumpers may exhibit substantially different deflection characteristics, rendering the game less enjoyable and entertaining and perhaps even necessitating an interruption of the game.
Various materials for filling the deflection cushion disclosed in my patent have been suggested, including those mentioned in the patent itself such as durable foam, feathers or various other materials. However, merely filling the tube with a collapsible material does not necessarily provide a desirable solution to the problems discussed above. Although some of these materials provide at least a partial solution to the problem of leaks in inflatable, sealed tubes, they may create other problems such as the storage of bulky, cumbersome, only partly-deflatable cushions.
Following the inflated tubular cushion just described, at least one bowling center used conventional foamed plastic blocks having a rectangular cross-section of about three and one-half inches high by about eight and one-half inches wide. Although the foam was compressible in the sense of a sponge, the storage volume of these foam blades was substantially the same as the volume in use, thus, requiring a large area for storing the units when not in use.